Structure and method for making a frame structure with supporting cross sections and process by which to manufacture it

ABSTRACT

A frame structure and process for its manufacture wherein supporting cross sections (1 a ) with at least one angle joint (11-19) and with reinforcing elements (4 a , 5 a ) arranged at a right angle to the angle joint. The reinforcing elements are structural plates or corrugated sheets in which the structures or corrugations run in the longitudinal direction of the angle joint and wherein the corrugated sheets have a lattice work like or lamellar like cross sectional form in the transverse direction.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention concerns a frame structure comprised of supporting cross sections with at least one angle joint. Reinforcing elements in the form of structural plates or corrugated sheets are arranged at a right angle with respect to the angle joint. The structures or corrugations extend in the longitudinal direction with respect to the angle joint. In the transverse direction with respect to the angle joint, the corrugated sheets have a lattice work like or lamellar like cross sectional form. The invention also concerns a process for manufacturing a frame structure of supporting cross sections, in particular for use in an aggressive environment such as waste water treatment plants or the like.

[0003] 2. Description of the Prior Art

[0004] In the prior art, steel girders have been made corrosion resistant by use of expensive coatings or costly alloying processes. In addition to the expensive mode of manufacturing, these girders also have a disadvantage in that the overall construction of coated steel girders is very heavy. Therefore, assembly as well as maintenance jobs require special hoisting equipment.

[0005] As described in DE 28 54 074, such steel girders are used, for example, in bridge superstructures wherein the structural supporting elements are arranged next to each other and transverse to the direction of the bridge. The structural supporting elements respectively carry an upper and a lower flange plate, with corrugated sheets arranged successively in the longitudinal direction of the bridge to serve as reinforcing elements in between. The corrugated sheets have approximately the same width as the flange plates. In this manner, modules are created, with cross beams or trusses, that provide uniform cross support in the transverse direction, so that the upper flange plate can be used over its entire width as a runway (page 15, 2^(nd) paragraph of DEOS 28 54 074).

[0006] Also known in the prior art, “sandwich structural elements” are used for more highly stressed lightweight constructions. In appropriate applications, they are made of aluminum in conjunction with other corrosion resistant materials. In this case, light core systems are used which are either conglutinated with relatively thin aluminum cover plates, or are also conjoined by a thermal fusion process, such as welding, soldering or such similar process. The protective cores can be composed of honeycombs, foamed materials or other lightweight materials and prevent bulging and buckling of the supporting sheet metal due to gravitational pull on the sheet level.

[0007] Such sandwich elements, for example, the so-called “HOBE” blocks, are relatively expensive and must be optimally adapted for support load stress coming from the given direction (Aluminum-paperback-14^(th) edition, page 312). Furthermore, such sandwich elements are somewhat prone to corrosion in aggressive conditions, so that a service life of several years without any problems is not assured.

[0008] The publication “Reinforced Plastics”, November 1996, volume 40, pages 28-30, shows supporting cross sections with H-profiles. In these cross-sections, the upper and lower flanges are reinforced with glass fibers or carbon fiber intermediate layers. Such supporting cross sections, sometimes referred to as “hybrid beams”, exhibit greater strength than other composite construction materials. However, in the event of fire, such hybrid beams present a risk of the release of toxic combustion by-products. Therefore, the hybrid beam has not been generally accepted as a supporting profile.

[0009] Therefore, there was a need in the prior art for new developments for supporting cross sections that are constructed of conventional materials such as described in German patent DE 197 07 133. These supporting cross sections are used to support sheet construction elements that cover containers filled with corrosive agents and they can be designed for flame proofing.

SUMMARY OF THE INVENTION

[0010] The invention disclosed herein improves upon the frame structure and, in particular, box girders with supporting cross sections of the type previously described herein. More specifically, as used in an aggressive environment where there is an explosion risk, such as with acid fumes having a pH value <2.5, the disclosed invention provides sufficient corrosion resistance and a service life of more than 10 years, without interim maintenance. At the same time, the disclosed invention is relatively light-weight and easy to manufacture.

[0011] As a further objective, the current invention is an improvement to known corrugated sheet carrier systems in that it develops new construction rigid design elements with various profile forms, preferably as box girders. The design elements can be plastically molded around at least one axis, prior to final assembly, and exhibit high rigidity and low sag after assembly. The design elements are sufficiently corrosion resistant in aggressive environments, in particular under acid fumes with a pH value of <2.5, even under a vibrating load, such as, for example, in stirring equipment and activated sludge tanks, among other examples.

[0012] The above objectives are achieved by an acid resistant and alkaline resistant frame structure of supporting cross sections. Preferably, the frame structure has right angle shaped profiles, but the frame structure can also have round, oval or honeycomb, or step-shaped sections. The supporting cross sections are comprised of structural plates or corrugated sheets 4, 5. The corrugated sheets are joined on the open sides 7, 10, in a form fitting and/or power adhering closing manner, over several angle joints 11-19, to form a frame structure, whereby the structures or corrugations run in the longitudinal direction of the supporting cross section, and the corrugated sheets exhibit a lattice work like or lamellar like cross sectional form in the transverse direction. The sheets/plates are joined on the open sides 7, 10 of the hollow space structures of the structural plates or corrugated sheets 4, 5, 6 with the angle joints, preferably by lamination, in a form fitting or power adhesion closing manner. When several elevations or wave crests and wave troughs in the structure or in the corrugated sheets 4, 5 abut against one another, they can be affixed together at these points. Preferably, for joining the structural plates or corrugated sheets at the elevations or wave crests and wave troughs, rotating fastening elements are arranged by punctual fixation at the elevations or troughs in the structural plates or corrugated sheets 4, 5 (refer to DE 197 07 133.3-24 which is hereby specifically incorporated by reference).

[0013] The angle joints used can be right angle shaped or rounded, closed or open profile cross sections. Examples are provided in FIG. 1a, b, and 1 c. The frame structure will especially increase its rigidity if the angle profiles are arranged with a closed box girder, whereby the structural plates or corrugated sheets function as braces/spacers.

[0014] Between at least two level angle joints, parallel running, strip-shaped, cut braces can be arranged, which are cut out of structural sheets, such as corrugated sheets, trapezoid profiles or honeycomb sheets, whereby the edges of cut run crosswise to the structure of the sheets and are embedded at a right angle to the level sheets, in a form closing manner.

[0015] In a preferred further development of the frame structure of supporting cross sections, in accordance with the invention, the braces are designed of individual corrugated sheet sections, whereby adjacent sheet sections meet one another at the respective wave crests or wave troughs and are also flexibly joined together at the points of contact.

[0016] Also in accordance with the invention, a further development of the frame structure of supporting cross sections is that prior to adhesion, several layers of corrugated sheet sections are formed together with the angle joints into arc-shaped supporting profiles, which are adhered in this position.

[0017] Also in accordance with the invention, the frame structure includes a special post configuration in which the individual supporting cross sections are provided with support flanges that have sheet sections or braces/spacers that are affixed prior to the application of level plastic sheets, In this way, only the respective outer end faces are joined with the level plastic sheets (FIG. 4). In addition, each post can receive a base plate to work as a vertical support.

[0018] The high load bearing rigidity of the frame structure with closed cross section is especially surprising, and such, that it can also be used as a horizontal beam. In the case of the arc-shaped design of the supporting cross section, in accordance with the invention, the arc, crosswise to the direction of corrugation, is achieved through gliding of the individual corrugated sheet sections upon one another. An elastic joint can be achieved in the contact zone, with screws, rivets or such similar, such that the mutual gliding of the individual spacer plates is not hindered (for this, refer to DE 197 07 133.3-24).

[0019] The hollow space structure resulting from this, as seen in cross section, is constructed as lamellar, whereby respectively two plates in the contact zone exhibit a common rotation point.

[0020] Other objects, advantages and embodiments of the presently disclosed invention will become apparent in a description of the presently preferred embodiment process.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] A presently preferred embodiment and method for making the same are shown and described in connection with the accompanying drawings wherein

[0022]FIG. 1a is a plan view of the frame structure.

[0023]FIG. 1b is a plan view of the frame structure having alternative angle joints;

[0024]FIG. 1c is an enlarged view of a partial plan view of the frame structure showing another, alternative angle joint in greater detail;

[0025]FIG. 2a is a perspective view of a preferred embodiment of the presently disclosed frame structure;

[0026]FIG. 2b is a partial plan view of the frame structure shown in FIG. 2a; and

[0027]FIG. 3 shows two elevational views of a modification of the frame structure that is shown in FIG. 2a.

DESCRIPTION OF A PRESENTLY PREFERRED EMBODIMENT

[0028] As shown in FIGS. 1a-1 c, in accordance with the invention, frame structures of supporting cross sections 1 a, 1 b and 2 a, 2 b, having angle joints 11-14 with reinforcement elements arranged in between. The reinforcement elements are corrugated sheets 4 a, 4 b and 5 a, 5 b, that extend in the longitudinal direction of the supporting cross sections, which, with their open end faces, form a lattice work like or lamellar like structure. The corrugated sheets are held together by angle joints 11-19 to form a square shaped or a triangular box girder (FIGS. 1a, 1 b) or an open frame structure (FIG. 1c).

[0029]FIG. 2a shows a perspective view of the lattice work like or lamellar like structure of a supporting cross section. As shown in FIG. 2a, the wave crests or the wave troughs are held shape, fitting in the cavities of the angle joints 19 a, 19 b. As shown in FIGS. 1c and 2 b, at the junction points are assembled in several laminate layers 7 a-7 e and 8 a, 8 b. Preferably, the contact points are created with punctual action on the wave apexes. In this way, the individual waves on a corrugated sheet can have a relative movement in the angle joints and thus, deflect internal stress buildup.

[0030] The relative movement of the mutually supporting wave crests is also an advantage in manufacturing frame structures that are used as support beams. FIG. 3 shows an example for the design of a vertical beam. The angle profiles 9 a-9 c are arranged on both sides of the angle joints 11, 12, which also act as spacers/braces. The relative movement of the angle joints also allows an even alignment of the support points A and the support point B.

[0031] A process for manufacturing a closed frame structure of supporting cross sections includes the following steps:

[0032] 1. Cut off long sections from corrugated sheets such that the longitudinal direction of the sections coincides with the wave direction.

[0033] 2. Next, several corrugated sheet sections, arranged in parallel, are secured to the contiguous wave crest points by, for example, screws, rivets or by lamination.

[0034] 3. As a further step, the corrugated sheet sections are brought into an arc-shape, such that the bending radius lies in the sheet plane of the corrugated sheet sections.

[0035] 4. The corrugated sheet sections are placed in the angle joints, such that they push up against the end sections of the wave crests, and are thus joined with the open, honeycomb like structure in a closing manner.

[0036] 5. Parallel to the corrugated sheet section, angle sections, which act as flange planes, are arranged at the angle joints and are not adhered to the corrugated sheet sections.

[0037] Advantageously, this process is a simple manufacturing process for various frame structures of bent supporting cross sections. Several corrugated sheet sections, affixed to one another (see item 2) also exhibit a minimum in stability in the bent state, such that the angle joints can be readily secured and adhered. Depending on the type of adhesive used, only short holding periods are required during hardening of the adhesive.

[0038] In a particularly advantageous design, angle joints 11-19 are comprised of angle sections with butt strap shaped elongations. In this way, the angle sections can be manufactured of metals, plastics or compounds and the angle joints can be manufactured of extrusion metals or pultrusion plastics.

[0039] For stronger attachment to the supporting cross sections, the angle joints are comprised of hollow profiles that have incisions or recesses 20 or elongations 21 or extensions for a form fitting conjoining with the supporting cross sections. Several fixation points 7 a-7 e, 8 a, 8 b are provided for joining the corrugated sheets at the wave crests or wave troughs within the supporting cross sections.

[0040] Preferably, the supporting profiles can be laminated into the angle joints 11-19, whereby the laminate at the conjoining site between the supporting cross section and the angle joint is comprised of at least one layer, which conjoins in a power adhering manner with the corrugated sheets of the supporting cross section.

[0041] If the cross section of the supporting profile is at least partially flattened at the conjoining site, the corrugated sheets can be molded to be power adhering into the conjoining site, after the impregnation of the glass fiber reinforced plastic laminate (GFK). The joining points formed is this way are particularly torsion-proof because the flattening increases the contact surface between the corrugated sheet and the angle joint.

[0042] While a presently preferred embodiment of the apparatus of the subject invention and a method of making the same is shown and described herein, the scope of the subject invention is not strictly limited thereto, but may be otherwise variously embodied within the scope of the following claims. 

What is claimed is:
 1. A frame structure having supporting cross sections, said frame structure comprising: at least one angle joint; and reinforcing elements that are arranged at a right angle with respect to said angle joint, said reinforcing elements having structures that extend in the longitudinal direction of the angle joint, and said reinforcing elements also having a lattice work like cross sectional form in the transverse direction, said reinforcing elements being conjoined on the open sides over several angle joints to a frame structure in a form fitting, power adhering manner.
 2. The frame structure of claim 1 wherein said reinforcing elements comprise structural plates.
 3. The frame structure of claim 1 wherein said reinforcing elements comprise corrugated sheets with corrugations that extend in the longitudinal direction of the angle joint.
 4. The frame structure of claim 3 wherein said reinforcing elements have a lamellar like cross sectional shape in the transverse direction.
 5. The frame structure of claims 1, 2, 3, or 4 wherein each of said angle joints define angle sections that encompass the open ends of the corrugated sheets with butt strap like elongations.
 6. The frame structure of claim 5 wherein the angle sections are composed of metals, plastics or compounds.
 7. The frame structure of claim 6 wherein the angle joints are composed of extrusion metals or pultrusion plastics.
 8. The frame structure of claim 7 wherein the angle joints include hollow sections having incisions (20) or elongations (21) for form closing jointing with the supporting cross sections.
 9. The frame structure of claim 8 wherein the angle joints are vertical supports, said frame structure further comprising: a respective base plate corresponding to each of said angle joints; and at least one supporting flange that is secured horizontally to the angle joints.
 10. The frame structure of claim 9 wherein the corrugated sheets have corrugations that include wave crests and wave troughs, said corrugated sheets having a plurality of securing points on said wave crests or wave troughs, within the supporting cross sections, to prevent torsion of the structural plates and corrugated sheets.
 11. A process for manufacturing a frame structure having a supporting cross section, said process comprising the steps of: Cutting at lease one section of corrugated sheet such that the section defines a generally rectangular surface having major and minor dimensions, the major dimension of the surface having an axis, with the direction of said axis being substantially parallel to the direction of the corrugations in the corrugated sheet: Arranging a plurality of said corrugated sheet sections in parallel and securing the wave crest points that are contiguous by fastening means; Forming the corrugated sheet sections into an arc-shape, wherein said sheet sections are formed such that the bending radius lies in the sheet plane of the corrugated sheet sections; Placing the corrugated sheet sections in the angle joints such that the sheet sections urge against the end sections of the wave crests and join with the open structure in a closing manner; and Assembling angle sections at the angle joints, said angle sections being parallel to the corrugated sheet section and not fastened to the corrugated sheet section such that said angle sections operate as flange planes.
 12. A process for manufacturing a frame structure according to claim 11, said process comprising the additional steps of: impregnating the glass fiber reinforced plastic laminate (GFK); and molding the corrugated sheets to be power adhering into the conjoining site, to the lattice work like or laminar like cross sections.
 13. A process for manufacturing a frame structure according to claim 12 wherein the supporting cross sections are laminated into the angle joints.
 14. A process for manufacturing a frame structure according to claim 13 wherein the laminate includes at least one layer at the conjoining site between the supporting cross section and the angle joint, said laminate being conjoined, in a power adhering manner, with the wave crests of the corrugated sheets of the supporting cross sections.
 15. A process for manufacturing a frame structure according to claim 13 wherein the laminate includes at least one layer at the conjoining site between the supporting cross section and the angle joint, said laminate being conjoined, in a power adhering manner, with the base of the corrugated sheets of the supporting cross sections. 